Description
In this thesis, we study two differentprimitives. Lossy trapdoor functions and zero-knwoledge proof systems.The lossy trapdoor functions (LTFs) arefunction families in which injective functionsand lossy ones are computationally indistin-guishable. Since their introduction, they havebeen found useful in constructing various cryp-tographic primitives. We give in this thesisefficient constructions of two different vari-ants of LTF: Lossy Algebraic Filter andR-LTF. With these two different variants, wecan improve the efficiency of the KDM-CCA(Key-Depended-Message Chosen-Ciphertext-Attack) encryption schemes, fuzzy extractoresand deterministic encryption.In the second part of this thesis, we in-vestigated on constructions of zero-knowledgeproof systems. We give the first logarithmic-size ring-signature with tight security usinga variant of Groth-KolhweizΣ-protocol in therandom oracle model. We also proposed onenew construction of lattice-based Designated-Verifier Non-Interactive Zero-Knowledge argu-ments (DVNIZK). Using this new construction, we build a lattice-based voting scheme in the standard model. lien: rien
Prochains exposés
-
Séminaire C2 à INRIA Paris
Emmanuel Thomé et Pierrick Gaudry Rachelle Heim Boissier Épiphane Nouetowa Dung Bui Plus d'infos sur https://seminaire-c2.inria.fr/ -
Attacking the Supersingular Isogeny Problem: From the Delfs–Galbraith algorithm to oriented graphs
Orateur : Arthur Herlédan Le Merdy - COSIC, KU Leuven
The threat of quantum computers motivates the introduction of new hard problems for cryptography.One promising candidate is the Isogeny problem: given two elliptic curves, compute a “nice’’ map between them, called an isogeny.In this talk, we study classical attacks on this problem, specialised to supersingular elliptic curves, on which the security of current isogeny-based cryptography relies. In[…]-
Cryptography
-